Post on 20-Mar-2018
transcript
5-1 Classifying Triangles
Today we will be learning how to classify triangles according to length of sides and measurement of the angles.
First we will learn to classify by the
ANGLES
Right triangles have ONE right angle
Acute Triangles have three acute angles
Smaller than 90o
Smaller than 90o
Smaller than 90o
Acute Angle
Obtuse Triangles have ONE obtuse angle
Obtuse Angle
We will now learn to classify triangles by their sides.
If you collapsed all of the sides they would form a line.
Equilateral Triangles have 3 equal sides
Isosceles Triangles have 2 equal sides.
Scalene Triangles have NO equal sides.
Classifying Triangles by Their Sides § EQUILATERAL – 3 congruent sides
§ ISOSCELES – at least two sides
congruent
§ SCALENE – no sides congruent
EQUILATERAL
ISOSCELES
SCALENE
1-3A
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1-3B
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1-3C
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1-3D
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You have now learned that triangles can be classified by either their sides or their angles.
10-1 ANGLES OF A TRIANGLE
1-1A
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1-2A
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1-2B
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1-2C
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1-2D
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1-2D
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1-2E
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1-2E
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1-2F
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1-2G
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1-2H
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1-2I
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1-2J
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1-2J
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GUIDED PRACTICE for Examples 3 and 4
5 .
Find the measures of the acute angles of the right triangle in the diagram shown.
26° and 64° ANSWER
The perimeter of a triangle is 29 cm. The length of the first side is twice the length of the second side. The length of the third side is 5 more than the length of the second side. Find the side lengths and then classify the triangle by its side lengths.
The ratio of angle measures of a triangle is 7:16:22. Find the angle measures and then classify the triangle by its angle measures.